1. Field of the Invention
The invention relates to electrical protective devices. More specifically, the invention relates to electrical protective devices mounted in collective assemblies.
2. Description of Related Art
As technology allows for further consolidation of circuitry, systems are becoming more compact. However, such compact considerations have been slow to implement in the field of electrical protective devices, such as circuit breakers and panelboards. The standard power distribution system includes typically one or more incoming power feed lines inserted through the top or bottom of a panelboard. The feed lines are connected to a main circuit breaker to switch overall power to the panelboard. From the main circuit breaker, the power from the feed lines is connected to longitudinal buss bars. A buss bar is used for each “hot” feed, typically one to three, with a central buss bar used for the neutral feed line and a ground. One or more circuit breakers are coupled to the buss bars. Typically, one or two vertical rows of circuit breakers are coupled to the buss bars. Distribution branch lines from the circuit breakers connect to electrical loads, such as motors and other electrical equipment, control systems, and other devices using electrical power.
With data processing centers, medical instrumentation, and other power sensitive equipment becoming prevalent, the electrical supply industry has sought ways to provide “clean” electrical power without interruption for such sensitive electrical loads. Uninterruptible power supply (UPS) devices are typically enclosed units with a battery and a control system that activates when the main AC power is interrupted to provides smooth DC power in a synthesized AC waveform. Thus, the electrical load often does not experience a substantive change in power during the interruption as long as the UPS battery can supply the power. Other protection can be gained without the battery backup by power line conditioners, known to those with ordinary skill in the art, that clean the incoming power. In some branch distribution lines, a UPS or power line conditioner can be hardwired between a circuit breaker and an electrical load. In actuality, the amount of wiring and components with controls can be enormous for some systems. The large amount contributes to a probability of downtime failure and the complexity contributes to difficulty with on-site repair in an efficient and timely manner. At times, the whole system has to be shut down to complete otherwise straightforward repairs.
Some vendors have sought to provide large systems for high KVA electrical loads that include the circuit breakers and UPS capabilities. A system offered by a popular vendor however is incompatible with standard panelboards. The main power feed lines are attached to non-standard locations in the cabinet and power is routed throughout the cabinet by buss bars to the various circuit breakers. A separate battery cabinet is attached to the circuit breaker cabinet for specific applications and hardwired together with the circuit breaker cabinet. The system is of such a design that the ultimate electrical load is required in an initial rating, and then the system is prewired with a large number of installed components that increases initial costs. To complete the system, power modules are installed into bays. If the system needs change, a significant amount of rewiring and design is required.
Thus, there remains a need to provide an electrical power system with UPS capabilities that can simplify the wiring and installed components, and advantageously be compatible with standard panelboards and circuit breakers mounted therein.